4.4 Borcherdt et al. (1991)

1) Reference

R. Borcherdt, C. M. Wentworth, A. Janssen, T. Fumal, and J. Gibbs, 1991, Methodology for Predictive GIS Mapping of Special Study Zones for Strong Ground Shaking in the San Francisco Bay Region, CA, Proc. 4th Int. Conf. Seismic Zonation, 545-552.

2) Formula

The relation between average shear velocity to a depth of 30m and average horizontal spectral amplification (0.4 – 2.0 sec) was evaluated using the observed records by the nuclear explosion and Loma Prieta Earthquake as follows;